Swallowing Flashcards
Describe the stages of swallowing
- Voluntary. Food compresses against mouth roof, tongue pushes food towards oropharynx
- Involuntary. Nasopharynx closed off by the soft palate and the uvula. The oropharynx is blocked by tongue movement, epiglottis flaps over the glottis closing the airway
- Involuntary. Sequential contraction of the constrictor muscles of the pharynx
- upper oesophageal sphincter opens and muscles propel food to stomach
What is the gag reflex?
- reflex elevation of the pharynx
- due to irritation of the oropharynx (could be due to vomiting)
- activates reflex arc - glossopharyngeal and vagus X
How can choking occur?
Failure to coordinate
could be due to intoxication or drugs
What is food lodging?
- irritation of the vagus nerve
- within the laryngopharynx
What is a tracheostomy
an incision in the windpipe made to relieve an obstruction to breathing (biro!)
What do the buccinator and suprahyoid muscles do?
- Manipulate food during chewing
- elevate hyoid bone and flatten floor of mouth during phase I of swallowing
What do the muscles of the palate do?
-Tense and elevate the hyoid bone, flatten floor of the mouth during phase I of swallowing
What do the muscles of the mouth floor do?
- Lower mandible if hyoid bone is fixed
- Raise hyoid bone and larynx if mandible is fixed
What does the infrahyoid muscle of the neck do?
- Fixes the hyoid bone enabling opening of the mouth
- draws down the hyoid bone and larynx (during phase III of swallowing)
What do the pharyngeal constrictor muscles do?
- 3 overlapping muscles (innervated by the pharyngeal plexus)
- Superior, middle and inferior constrictor
What type of muscle is in the oesophagus?
the first 1/3 is striated
the last 1/3 is smooth
(the middle is a fix)
List the functions of saliva
Lubricant for mastication, swallowing and speech
Oral hygiene - wash, immunity (antibacterial, antiviral, antifungal)
Bicarbonate/carbonate buffer for rapid neutralisation - maintain pH
Digestive enzymes
Provide an aqueous environment for taste
What are the 3 main salivary glands? Are they serous or mucinous?
Parotid gland = serous
Submandibular glands = serous and mucinous
Sublingual glands = mainly mucinous
Which salivary glands are continuously active and which is active when stimulated?
Submandibular and sublingual are continuously active
Parotid has no measurable unstimulated secretion but is main source of saliva when secreted
Parotid gland - shape, duct, structures, innervation
Superficial triangular outline
Duct = Stenson’s duct - crosses masseter, pierces buccinator and enters oral cavity
Structures passing through it: External carotid and terminal branches, retromandibular vein, facial nerve and branches to muscles of facial expression
Innervation: parasympathetics of glossopharyngeal
